Figure 4 shows that brain sections harvested from brains treated with rAAV2/IL12 (A, B, C, D) show small tumor size and prominent dark-brown ED1 positive cells infiltrating in four quadrants of the tumor; those with rAAV2/GFP (E, F) and PBS (G, H), show sparse dark brown ED1 positive cells infiltrating in four quadrants of the tumor; while the brain section treated with nothing (I) does not show dark-brown stained cells. The gene discussed is EDA; the disease is neoplasm.